What is this knob for?

[jdfet1]

Hey guys,
I was looking at my bike the other day trying to familiarize myself with it when I noticed a knob near the middle of the motor. I saw it from the 'passenger side' of the bike. Is this for the timing chain? Shouldnt it be a self adjuster? I wondered if this was contributing to my chirping sound.
I need to get a manual for it yet but in the mean time, I knew you guys have all of this stuff covered!

[TheCafeKid]

It IS the cam chain adjuster, and YES its automatic. In other words, DONT touch it. The knob is basicly for the times when you take the adjuster out to rebuild or clean the motor or adjustor or both, and need to reset it.

[bwringer]

Get yer hot naked stripped down cam chain tensioner rebuild photos here and satisfy your curiosity!

http://bwringer.com/gs/camchaintens.html

[Zooks]

Some (early model?) bikes also had an idle adjuster down there as well. It usually had a white plastic knob. It sits higher than the chain tensioner though, on top of the carbs.